INVESTIGADORES
MIGUEL Maria De La Paz
congresos y reuniones científicas
Título:
DEPTH PROFILING BY CONFOCAL RAMAN MICROSCOPY: DETERMINATION OF THE AXIAL POINT SPREAD FUNCTION
Autor/es:
MIGUEL, MARÍA DE LA PAZ; TOMBA, J. PABLO; CAPPARELLI, CLARA
Lugar:
Bahía Blanca
Reunión:
Congreso; IX Simposio Argentino de Polímeros (SAP2011); 2011
Institución organizadora:
Comité Organizador SAP 2011
Resumen:
In-depth CRM studies of transparent materials are typically carried out with standard metallurgical objectives since minimal sample preparation is required. However, it is well known that Confocal Raman Measurements are optically distorted by a combination of laser refraction, diffraction and the presence of the confocal aperture. All these effects conspire against data quality and definition. Those distortions can be fully characterized by the knowledge of the instrumental Point Spread Function (PSF). Some theoretical models have been developed by the estimation of the PSF, which have assisted the interpretation of depth profiles . However, it would be highly desirable to directly charaterize the PSF via experiments. This knowledge would help to improve existing models and to optimize instrumental design.
This work describes how to determine and characterize actual PSF values within the material, where distortions by refraction operate. The
experimental set-up was built by burying a silicon wafer under a polymeric substrate with a known variable thickness. Via Depth Slicing (DS) of the specimen in the xz plane and a careful data processing, we were able to obtain a precise characterization of the shape of the PSF as a function of the nominal focusing depth.